Interpretation of the cosmic ray positron and antiproton fluxes

Abstract

The spectral shape of cosmic ray positrons and antiprotons has been accurately measured in the broad kinetic energy range 1-350 GeV. In the higher part of this range (E > 30 GeV) the e+ and pbar are both well described by power laws with spectral indices gamma[e+] = 2.77 +-0.02 and gamma[pbar] = 2.78 +- 0.04 that are approximately equal to each other and to the spectral index of protons. In the same energy range the positron/antiproton flux ratio has the approximately constant value 2.04+-0.04, that is consistent with being equal to the ratio e_/pbar calculated for the conventional mechanism of production, where the antiparticles are created as secondaries in the inelastic interactions of primary cosmic rays with interstellar gas. The positron/antiproton ratio at lower energy is significantly higher (reaching the approximate value e+/pbar = 100 for E around 1 GeV), but in the entire energy range 1-350 GeV, the flux ratio is consistent with being equal to ratio of the production rates in the conventional mechanism, as the production of low energy antiprotons is kinematically suppressed in collisions with a target at rest. These results strongly suggest that cosmic ray positrons and antiprotons have a common origin as secondaries in hadronic interactions. This conclusion has broad implications for the astrophysics of cosmic rays in the Galaxy.

arXiv commentRextex 23 pages 9 figures. Paper replaced to match with version accepted in Phys.Rev.D. Included more critical discussion and relevant citations

References in corpus (31)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• Observation of an anomalous positron abundance in the cosmic radiation
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• PAMELA Measurements of Cosmic-ray Proton and Helium Spectra
• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• The energy spectrum of cosmic-ray electrons at TeV energies
• Measurement of separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope
• PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy
• Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S
• Discrepant hardening observed in cosmic-ray elemental spectra
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Constraints on cosmic-ray propagation models from a global Bayesian analysis
• The cosmic-ray positron energy spectrum measured by PAMELA
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• Flavor Composition and Energy Spectrum of Astrophysical Neutrinos
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• Measurement of boron and carbon fluxes in cosmic rays with the PAMELA experiment
• AMS-02 antiprotons, at last! Secondary astrophysical component and immediate implications for Dark Matter
• AMS02 results support the secondary origin of cosmic ray positrons
• Inclusive production of charged kaons in p+p collisions at 158 GeV/c beam momentum and a new evaluation of the energy dependence of kaon production up to collider energies
• Solution to the cosmic ray anisotropy problem
• The origin of the spectral intensities of cosmic-ray positrons
• Observations of the Li, Be, and B isotopes and constraints on cosmic-ray propagation
• Secondary antiprotons as a Galactic Dark Matter probe
• The boron-to-carbon abundance ratio and Galactic propagation of cosmic radiation
• What can we really learn from positron flux 'anomalies'?
• Examination of uncertainties in nuclear data for cosmic ray physics with the AMS experiment
• Secondary Production as the Origin for the Cosmic Ray Positron Excess

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• The origin of Galactic cosmic rays: challenges to the standard paradigm
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• Diffuse Galactic gamma ray flux at very high energy
• Imprints of Cosmic Rays in Multifrequency Observations of the Interstellar Emission
• AMS-100: The Next Generation Magnetic Spectrometer in Space -- An International Science Platform for Physics and Astrophysics at Lagrange Point 2
• Galactic factories of cosmic-ray electrons and positrons
• Gamma-ray halos around pulsars as the key to understanding cosmic ray transport in the Galaxy
• Cosmic ray signatures of a 2-3 Myr old local supernova
• On the Spectrum of Electrons Accelerated in Supernova Remnants
• Features in cosmic-ray lepton data unveil the properties of nearby cosmic accelerators
• Diffuse γ-ray emission from self-confined cosmic rays around Galactic sources
• On particle acceleration and transport in plasmas in the Galaxy: theory and observations
• Signature of Energy Losses on the Cosmic Ray Electron Spectrum
• On the spectrum of stable secondary nuclei in cosmic rays
• Where are Milky Way's Hadronic PeVatrons?
• The spectral shapes of the fluxes of electrons and positrons and the average residence time of cosmic rays in the Galaxy
• Effects of reacceleration and source grammage on secondary cosmic rays spectra
• Interpretation of the excess of antiparticles within a modified paradigm of galactic cosmic rays
• Theoretical interpretation of Pass 8 Fermi-LAT $e^{+}+e^{-}$ data
• Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies
• Implications of a possible TeV break in the cosmic-ray electron and positron flux
• Nonsecondary origin of cosmic ray positrons
• Selected Topics in Cosmic Ray Physics
• $e^{+}$ and $\bar{p}$ production in $pp$ collisions and the cosmic-ray $e^{+}/\bar{p}$ flux ratio
• On the origin of the spectral features observed in the cosmic ray spectrum
• Examining the secondary product origin of cosmic ray positrons with the latest AMS-02 data
• Regions of suppressed diffusion around supernova remnants?
• Deflection of charged massive particles by a four-dimensional charged Einstein-Gauss-Bonnet black hole
• Direct measurements of cosmic rays and their possible interpretations
• Deciphering the Electron Spectral Hardening in AMS-02
• Non-linear Cosmic Ray Propagation
• The self-control of Cosmic Rays